They were made in both 45 Colt and 45 S&W (Schofield). You can shoot Schofield rounds in a Colt chamber.
As to Black Powder fouling, that has been a problem since 1873! The S&W's, Colts, Merrill & Hubert, and just about every other cartridge revolver had issues. A lot of the problem is powder quality and having enough lube UNDER the bullet. Cap and ball revolvers had the same issue, but people learned to fill the front of the cylinder with some form of grease! (Beef and sheep tallow were most common) If shooting black powder cartridges, you can dip the loaded round in Crisco before loading (in warm weather it melts and runs off, so use a 50/50 mix of Crisco/Paraffin) This works in single shot rifles also, but not lever actions!
The hinge (Top Break) action is not as strong as a top strap revolver. I is safe with all factory ammo, but for a longer life don't use the heaviest load you can. I stick to "Target" loads in my No.3 44 Russian repos! Usually anything sold as "Cowboy Action" ammo is in the light duty/target family.
Col. Schofield's modifications to the original No.3 revolver, were to help reloading during a cavalry charge. Let me know how that works out for you! Remember, you saber goes in the right hand and the revolver in the left, and the reigns in your teeth!
Ivan